From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7AF8E9412F for ; Fri, 6 Oct 2023 21:46:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233701AbjJFVqj (ORCPT ); Fri, 6 Oct 2023 17:46:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233704AbjJFVqi (ORCPT ); Fri, 6 Oct 2023 17:46:38 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F961BE; Fri, 6 Oct 2023 14:46:37 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD177C433C8; Fri, 6 Oct 2023 21:46:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1696628797; bh=PCl4CBWRE6qLOar8gKrsXLI2bjflznbGFV52K5Zf7g0=; h=Date:To:From:Subject:From; b=sCoVwAV9QVPl9vtKnDdxldauXG+d40T4+MqQo92JEm1/Ncsy7B48wtFahvtVKgT1/ /mFRM5Ykk3vKAoGBHUpibwJU/a7/LZnk2xdColQsFOfBjTXvtumpoT3twhfaIVl9T6 La3D+v8EEczoGL/5T/jT9VzBkpB9aTUVxN8Rhx7s= Date: Fri, 06 Oct 2023 14:46:33 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, stable@vger.kernel.org, osalvador@suse.de, naoya.horiguchi@nec.com, shikemeng@huaweicloud.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-page_alloc-correct-start-page-when-guard-page-debug-is-enabled.patch removed from -mm tree Message-Id: <20231006214636.AD177C433C8@smtp.kernel.org> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The quilt patch titled Subject: mm/page_alloc: correct start page when guard page debug is enabled has been removed from the -mm tree. Its filename was mm-page_alloc-correct-start-page-when-guard-page-debug-is-enabled.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Kemeng Shi Subject: mm/page_alloc: correct start page when guard page debug is enabled Date: Wed, 27 Sep 2023 17:44:01 +0800 When guard page debug is enabled and set_page_guard returns success, we miss to forward page to point to start of next split range and we will do split unexpectedly in page range without target page. Move start page update before set_page_guard to fix this. As we split to wrong target page, then splited pages are not able to merge back to original order when target page is put back and splited pages except target page is not usable. To be specific: Consider target page is the third page in buddy page with order 2. | buddy-2 | Page | Target | Page | After break down to target page, we will only set first page to Guard because of bug. | Guard | Page | Target | Page | When we try put_page_back_buddy with target page, the buddy page of target if neither guard nor buddy, Then it's not able to construct original page with order 2 | Guard | Page | buddy-0 | Page | All pages except target page is not in free list and is not usable. Link: https://lkml.kernel.org/r/20230927094401.68205-1-shikemeng@huaweicloud.com Fixes: 06be6ff3d2ec ("mm,hwpoison: rework soft offline for free pages") Signed-off-by: Kemeng Shi Acked-by: Naoya Horiguchi Cc: Matthew Wilcox (Oracle) Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/page_alloc.c~mm-page_alloc-correct-start-page-when-guard-page-debug-is-enabled +++ a/mm/page_alloc.c @@ -6475,6 +6475,7 @@ static void break_down_buddy_pages(struc next_page = page; current_buddy = page + size; } + page = next_page; if (set_page_guard(zone, current_buddy, high, migratetype)) continue; @@ -6482,7 +6483,6 @@ static void break_down_buddy_pages(struc if (current_buddy != target) { add_to_free_list(current_buddy, zone, high, migratetype); set_buddy_order(current_buddy, high); - page = next_page; } } } _ Patches currently in -mm which might be from shikemeng@huaweicloud.com are mm-page_alloc-remove-unnecessary-check-in-break_down_buddy_pages.patch mm-page_alloc-remove-unnecessary-next_page-in-break_down_buddy_pages.patch